Refractory slide gates are used in metallurgical vessels in order to control removal of molten metal therefrom. They are subject to extremely high temperatures and the corrosive action of the molten metals passing through the openings in slide gate plates and, consequently, efforts have been constantly undertaken in order to improve the erosion and/or corrosion resistance of slide gates.
At the present time, alumina-carbon slide gate plates have been shown to have improved properties compared to burned high alumina slide gates with a mullite bond. However, there are even with such compositions unsatisfactory drawbacks. Primarily, there is the lack of resistance to oxidation of the carbon and high costs due to the necessity to burn the shape under reducing conditions to produce SiC bonds which result from the reaction of silicon with carbon in the matrix of the shape.
Efforts to overcome these problems of lack of oxidation resistance and high processing costs have not been satisfactory.